Matched tcr joule heater designs for electrostatic chucks

ABSTRACT

A method of forming a substrate support in a substrate processing system includes forming at least one ceramic layer and arranging a plurality of thermal elements adjacent to the ceramic layer in one or more thermal zones. Each of the thermal zones includes at least one of the thermal elements and each of the thermal elements includes a first resistive material having a positive thermal coefficient of resistance (TCR) and a second resistive material having a negative TCR. The second resistive material is electrically connected to the first resistive material. At least one of the first resistive material and the second resistive material of each of the thermal elements is electrically connected to a power supply to receive power and each of the thermal elements heats a respective one of the thermal zones based on the received power.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure is a divisional of U.S. patent application Ser.No. 15/292,688, filed on Oct. 13, 2016, which claims the benefit of U.S.Provisional Application No. 62/258,825, filed on Nov. 23, 2015. Theentire disclosures of the applications referenced above are incorporatedherein by reference.

FIELD

The present disclosure relates to substrate processing systems, and moreparticularly to systems and methods for controlling the temperature of asubstrate support in a substrate processing system.

BACKGROUND

The background description provided here is for the purpose of generallypresenting the context of the disclosure. Work of the presently namedinventors, to the extent it is described in this background section, aswell as aspects of the description that may not otherwise qualify asprior art at the time of filing, are neither expressly nor impliedlyadmitted as prior art against the present disclosure.

Substrate processing systems may be used to treat substrates such assemiconductor wafers. Example processes that may be performed on asubstrate include, but are not limited to, a chemical vapor deposition(CVD), atomic layer deposition (ALD), and/or other etch, deposition, orcleaning processes. A substrate may be arranged on a substrate support,such as a pedestal, an electrostatic chuck (ESC), etc. in a processingchamber of the substrate processing system. During etching, gas mixturesincluding one or more precursors may be introduced into the processingchamber and plasma may be used to initiate chemical reactions.

During process steps, temperatures of various components of the system,and the substrate itself, may vary. These temperature variations mayhave undesirable effects on the resulting substrates (such as defects ornon-uniform critical dimensions). Accordingly, substrate processingsystems may attempt to control temperatures of various components andthe substrates during processing.

SUMMARY

A substrate support for supporting a substrate in a substrate processingsystem includes a plurality of thermal elements. The thermal elementsare arranged in one or more thermal zones, and each of the thermal zonesincludes at least one of the thermal elements. Each of the thermalelements includes a first resistive material having a positive thermalcoefficient of resistance and a second resistive material having anegative thermal coefficient of resistance. The second resistivematerial is electrically connected to the first material. At least oneof the first resistive material and the second resistive material ofeach of the thermal elements is electrically connected to a power supplyto receive power, and each of the thermal elements heats a respectiveone of the thermal zones based on the received power. At least oneceramic layer is arranged adjacent to the thermal elements.

A method of forming a substrate support in a substrate processing systemincludes forming at least one ceramic layer and arranging a plurality ofthermal elements adjacent to the ceramic layer. The thermal elements arearranged to correspond to one or more thermal zones, and each of thethermal zones includes at least one of the thermal elements. Each of thethermal elements includes a first resistive material having a positivethermal coefficient of resistance and a second resistive material havinga negative thermal coefficient of resistance. The second resistivematerial is electrically connected to the first material. At least oneof the first resistive material and the second resistive material ofeach of the thermal elements is electrically connected to a power supplyto receive power. Each of the thermal elements heats a respective one ofthe thermal zones based on the received power.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description, the claims and the drawings. Thedetailed description and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of thedisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a functional block diagram of an example substrate processingsystem including a substrate support according to the principles of thepresent disclosure;

FIGS. 2A and 2B show an example heating plate including a plurality ofheating elements in a side view and a top plan view, respectively,according to the principles of the present disclosure;

FIG. 3 illustrates example wiring of a plurality of heating elementsaccording to the principles of the present disclosure;

FIG. 4 illustrates another example wiring of a plurality of heatingelements according to the principles of the present disclosure;

FIGS. 5A, 5B, and 5C show example arrangements of heating layersincluding a first material having a first temperature coefficient ofresistance (TCR) and a second material having a second TCR according tothe principles of the present disclosure; and

FIGS. 6A, 6B, 6C, and 6D show configurations of a single heating layerincluding both a first heating material and a second heating materialaccording to the principles of the present disclosure.

In the drawings, reference numbers may be reused to identify similarand/or identical elements.

DETAILED DESCRIPTION

In a substrate processing system, temperatures of a substrate support,such as an electrostatic chuck (ESC), may be controlled during processsteps. For example, different processes and respective steps may requirethat a substrate is maintained at the same or different temperatures. Acontact surface temperature of the substrate support may be controlledto maintain the substrate at desired temperatures. For example only, thesubstrate support may include a heating plate (e.g., a ceramic heatingplate). The substrate may be arranged on the heating plate. Accordingly,the temperature of the heating plate is controlled to achieve thedesired temperatures of the substrate.

The temperature of the heating plate may be controlled by selectivelyproviding current to a plurality of heating elements, which may beimplemented using resistive materials embedded within the heating plate.In other words, the heating plate implements resistive (i.e., joule)heating. The heating elements may be arranged within a plurality ofzones of the substrate support (e.g., a multi-zone substrate support).For example only, the substrate support may include 2, 3, 4, or 100 ormore zones. Each zone may include one or more heating elements.

Resistive materials may have an associated temperature coefficient ofresistance (TCR), which corresponds to an increased resistance (forpositive TCR materials) or a decreased resistance (for negative TCRmaterials) as temperature increases. Accordingly, the power provided tothe heating elements to control the temperature of the substrate supportvaries with temperature, causing variations in power output, temperaturecontrol efficiency and accuracy, etc. For example only, a materialhaving a TCR of 0.3% per ° C. experiences a 60% change in resistance atfrom 0° C. to 200° C.

Systems and methods according to the present disclosure implement pairsof matched resistive heating elements having complementary positive andnegative TCRs. For example, each heating element includes a firstmaterial having a positive TCR and a second material having a negativeTCR. For example only, materials having a positive TCR include, but arenot limited to, highly-doped platinum, tungsten ruthenium in oxides,etc. and materials having a negative TCR include, but are not limitedto, semiconductors, low percent doped metals in oxides, etc.Accordingly, as the temperature of the respective zone of the substratesupport varies, the resistance of the heating element including thematched positive and negative TCR materials remains substantiallyconstant and/or changes at lower rates. In some examples, the firstmaterial and the second material are connected in series. In otherexamples, the first material and the second material are connected inparallel. The first material and the second material may be alignedvertically in different planes of the heating plate. In some examples,the first and second materials are spaced apart in different layers andanother layer (e.g., a dielectric layer, a bus layer, etc.) is arrangedbetween the first and second materials. In other examples, the firstmaterial and the second material may be coplanar (e.g., interwoven in asame plane of the heating plate).

Referring now to FIG. 1, an example substrate processing system 100 forperforming etching using RF plasma is shown. The substrate processingsystem 100 includes a processing chamber 102 that encloses othercomponents of the substrate processing system 100 and contains the RFplasma. The substrate processing system 100 includes an upper electrode104 and a substrate support 106, such as an electrostatic chuck (ESC).During operation, a substrate 108 is arranged on the substrate support106.

For example only, the upper electrode 104 may include a showerhead 109that introduces and distributes process gases. The showerhead 109 mayinclude a stem portion including one end connected to a top surface ofthe processing chamber. A base portion is generally cylindrical andextends radially outwardly from an opposite end of the stem portion at alocation that is spaced from the top surface of the processing chamber.A substrate-facing surface or faceplate of the base portion of theshowerhead includes a plurality of holes through which process gas orpurge gas flows. Alternately, the upper electrode 104 may include aconducting plate and the process gases may be introduced in anothermanner.

The substrate support 106 includes a conductive baseplate 110 that actsas a lower electrode. The baseplate 110 supports a heating plate 112,which may correspond to a ceramic multi-zone heating plate. A thermalresistance layer 114 may be arranged between the heating plate 112 andthe baseplate 110. The baseplate 110 may include one or more coolantchannels 116 for flowing coolant through the baseplate 110.

An RF generating system 120 generates and outputs an RF voltage to oneof the upper electrode 104 and the lower electrode (e.g., the baseplate110 of the substrate support 106). The other one of the upper electrode104 and the baseplate 110 may be DC grounded, AC grounded or floating.For example only, the RF generating system 120 may include an RF voltagegenerator 122 that generates the RF voltage that is fed by a matchingand distribution network 124 to the upper electrode 104 or the baseplate110. In other examples, the plasma may be generated inductively orremotely. Although, as shown for example purposes, the RF generatingsystem 120 corresponds to a capacitively coupled plasma (CCP) system,the principles of the present disclosure may also be implemented inother suitable systems, such as, for example only transformer coupledplasma (TCP) systems, CCP cathode systems, etc.

A gas delivery system 130 includes one or more gas sources 132-1, 132-2,. . . , and 132-N (collectively gas sources 132), where N is an integergreater than zero. The gas sources supply one or more precursors andmixtures thereof. The gas sources may also supply purge gas. Vaporizedprecursor may also be used. The gas sources 132 are connected by valves134-1, 134-2, . . . , and 134-N (collectively valves 134) and mass flowcontrollers 136-1, 136-2, . . . , and 136-N (collectively mass flowcontrollers 136) to a manifold 140. An output of the manifold 140 is fedto the processing chamber 102. For example only, the output of themanifold 140 is fed to the showerhead 109.

A temperature controller 142 may be connected to a plurality of heatingelements (e.g., thermal control elements, or TCEs) 144 arranged in theheating plate 112. For example, the heating elements 144 may include,but are not limited to, macro heating elements corresponding torespective zones in a multi-zone heating plate and/or an array of microheating elements disposed across multiple zones of a multi-zone heatingplate. The temperature controller 142 may be used to control theplurality of heating elements 144 to control a temperature of thesubstrate support 106 and the substrate 108. Each of the heatingelements 144 according to the principles of the present disclosureincludes a first material having a positive TCR and a second materialhaving a negative TCR as described below in more detail.

The temperature controller 142 may communicate with a coolant assembly146 to control coolant flow through the channels 116. For example, thecoolant assembly 146 may include a coolant pump and reservoir. Thetemperature controller 142 operates the coolant assembly 146 toselectively flow the coolant through the channels 116 to cool thesubstrate support 106.

A valve 150 and pump 152 may be used to evacuate reactants from theprocessing chamber 102. A system controller 160 may be used to controlcomponents of the substrate processing system 100. A robot 170 may beused to deliver substrates onto, and remove substrates from, thesubstrate support 106. For example, the robot 170 may transfersubstrates between the substrate support 106 and a load lock 172.Although shown as separate controllers, the temperature controller 142may be implemented within the system controller 160.

Referring now to FIGS. 2A and 2B, an example heating plate 200 (e.g., aceramic heating plate) including a plurality of heating elements 204 isshown in a side cross-sectional view and a top plan view, respectively.Each of the heating elements 204 includes a first material 208 and asecond material 212. The first material 208 may have a positive TCRwhile the second material 212 may have a negative TCR, or vice versa.Respective absolute values of the TCRs of the plurality of heatingelements 204 may be the same or different. In other words, the firstmaterial 208 of one of the heating elements 204 may have a firstpositive TCR while the first material 208 of another one of the heatingelements 204 may have the same first positive TCR or a second, differentpositive TCR. The first material 208 and the second material 212 may bespaced apart as shown, with a layer arranged therebetween. In someexamples, a dielectric layer, a bus layer, etc. is arranged therebetweenas described in more detail below. The heating elements 204 may becompletely or partially encapsulated by one or more ceramic layers ofthe heating plate 200.

Although the heating elements 204 are described herein as being arrangedwithin ceramic layers, in some embodiments the heating elements 204 maybe formed in a metallized layer that is deposited on a bottom surface ofa ceramic layer (e.g., either prior to or subsequent to the respectiveceramic layer being fired). For example only, the metallized layer maycomprise tungsten, palladium, silver, etc. to act as a heating layer. Insome examples, the metallized layer may be deposited via PVD,electroless deposition, electroplating, etc. prior to the firing of theceramic layer. In other examples, the metallized layer may be depositedvia screen-printing prior to the firing of the ceramic layer.

Although as shown the first material 208 is arranged directly above thesecond material 212 in a vertical direction, this illustration is forexample only and other arrangements may be used as described below inmore detail. For example, the first material 208 and the second material212 may be offset in a lateral direction such that the first material208 only partially overlaps the second material 212, partially overlapsthe second material 212 of another heating element, etc. In someexamples, the first material 208 may be completely offset from thesecond material 212 in a lateral direction (i.e., the first material 208does not overlap the second material 212 of the same heating element),and the first material 208 and the second material 212 may be coplanar.

Each of the heating elements 204 may correspond to a different zone ofthe heating plate 200, or multiple heating elements 204 may correspondto a single zone. Although shown arranged in a rectangular grid, inother examples the heating elements 204 may be arranged in otherconfigurations such as concentric rings, a hexagonal grid, etc.

Each of the heating elements 204 is connected to power supply lines 216and/or power return lines 220 as shown schematically. The connections ofthe power supply lines 216 and the power return lines 220 are shown forexample only, and other arrangements may be used. For example, a buslayer 224 may be arranged below the heating elements 204 including thepower supply lines 216 and the power return lines 220. Connectionsbetween the bus layer 224 and the heating elements 204 are providedusing respective vias 228. In the present example, no two heatingelements 204 share a same pair of the power supply lines 216 and thepower return lines 220. Accordingly, by selectively switching respectivepower supply lines 216 and power return lines 220, each of the heatingelements 204 can be individually provided with power independently ofothers of the heating elements 204. In some implementations, to preventcrosstalk between different heating elements 204, a rectifier (e.g. adiode, FIG. 3) may be serially connected between each of the heatingelements 204 and the power supply lines 216, or between each of theheating elements 204 and the power return lines 220. The rectifier canbe arranged within the heating plate (e.g., in the bus layer 224) or anysuitable location. In other implementations, other current blockingelements (e.g., solid state switches) may be used to prevent crosstalk.

In examples, the first material 208 and the second material 212 may eachinclude composites of various insulators and conductors. For exampleonly, the first material 208 may include Al₂O₃, SiO₂, Si₃N₄, AlN, Al,Cu, Mo, W, Au, Ag, Pt, Pd, C, MoSi₂, WC, SiC, and mixtures thereofresulting in a positive TCR. Conversely, the second material 212 mayinclude Si or Ge (e.g., applied in powder form as a screen-printed ink),metal oxides including, but not limited to, spinel phase manganates,cobalt oxides, nickel oxides, and mixtures thereof (e.g., Fe₂O₃ and Ti,NoO and Li, etc.), Rh, Ru, Pt, W, and other known low-temperaturesemiconducting metal oxides. Other materials that may suitable in someimplementations include C, Ni, Cr, and Co. The materials 208 and 212 maybe formed by combining powders (for example only, having particle sizesfrom 0.2 to 10 microns) of an insulator and a conductor with a suitableliquid (e.g. methanol, ethanol, acetone, isopropyl alcohol, water,mineral oil, or a mixture thereof) into a slurry, and sintering theslurry.

The heating plate 200 may be formed from ceramic using various methods.For example, a mixture of ceramic powder, binder and liquid may bepressed into ceramic layer sheets (which may be referred to as “greensheets”). The green sheets are dried and holes are punched in the greensheets to form vias (e.g., corresponding to the vias 228). The vias arefilled with conductive material (e.g., a slurry of conducting powder).The power supply lines 216 and the power return lines 220 correspondingto a first bus or routing layer are formed on the green sheets. Forexample only, the power supply lines 216 and the power return lines 220are formed on the ceramic green sheets by screen printing a slurry ofconducting powder (e.g. W, WC, doped SiC, MoSi₂, etc.), pressing aprecut metal foil, spraying a slurry of conducting powder, and/or othersuitable techniques.

The heating elements 204 are then formed on the ceramic green sheets.For example only, the heating elements 204 may be formed by screenprinting or spraying a slurry of insulator and conductor powders in oneor more heating layer green sheets (e.g., first heating layer greensheets corresponding to a first material and second heating layer greensheets corresponding to a second material). For example, the firstheating layer green sheets may be deposited on the ceramic green sheets,an intermediate layer (e.g., another ceramic green sheet layer, adielectric layer, and/or a second bus layer) may be formed on the firstheating layer green sheets. Additional vias may be formed through thefirst heating layer green sheets to connect the first bus layer and/orthe first heating layer green sheets to the second bus layer. The secondheating layer green sheets are then formed on the intermediate layer.

The ceramic green sheets and the heating layer green sheets are alignedand then bonded together by sintering. For example, in one example, theceramic green sheets and the first heating layer green sheets may bealigned and bonded together prior to forming the intermediate layer. Theintermediate layer is then formed, aligned, and bonded to the firstheating layer, and the second heating layer green sheets are formed,aligned, and bonded to the intermediate layer. In other examples, theceramic green sheets, the first heating layer green sheets, theintermediate layer, and the second heating layer green sheets arealigned and bonded together in a same process step. Other ceramic greensheets may be formed on the heating layer green sheets as describedabove to form a substantially contiguous ceramic layer completelyencapsulating the first and second heating materials of the heatinglayer.

Referring now to FIG. 3, example wiring of a plurality of heatingelements 300 is shown schematically. In this example, a first materialTCR1 (e.g., having a positive TCR) and a second material TCR2 (e.g.,having a negative TCR) are connected in series. For example, a first endof the first material TCR1 is connected to a power supply bus 304 and asecond end of the first material TCR1 is connected to a first end of thesecond material TCR2. A second end of the second material TCR2 isconnected to a power return bus 308. In some embodiments, a diode 312(e.g., functioning as a rectifier as described above in FIGS. 2A and 2B)may be serially connected between each of the heating elements 300 andthe power supply bus 304. As shown in FIG. 3, nodes 316 indicate aconnection between intersecting wires, and intersecting wires that donot include the node 316 are not connected together.

Referring now to FIG. 4, another example wiring of a plurality ofheating elements 400 is shown schematically. In this example, a firstmaterial TCR₁ (e.g., having a positive TCR) and a second material TCR₂(e.g., having a negative TCR) are connected in parallel. For example,respective first ends of the first material TCR₁ and the second materialTCR₂ are connected to a power supply bus 404 and respective second endsof the first material TCR₁ and the second material TCR₂ are connected toa power return bus 408. In some embodiments, a diode 412 may be seriallyconnected between each of the heating elements 400 and the power supplybus 404. As shown in FIG. 4, nodes 416 indicate a connection betweenintersecting wires, and intersecting wires that do not include the node416 are not connected together.

FIGS. 5A, 5B, and 5C show example arrangements of heating layerscorresponding to a first material having a first (e.g., positive) TCRand a second material having a second (e.g., negative) TCR. As shown inan example in FIG. 5A, a layer 500 corresponds to a first ceramic layerof green sheets, which may include a bus layer 504 formed thereon. Vias508 are formed in the layer 500 to connect the bus layer 504 to a powersupply and a power return. Green sheets including a first heating layer512 and a second heating layer 516 are formed on the layer 500. Adielectric layer 520 may be formed between the first heating layer 512and the second heating layer 516. A layer 524 corresponding to a secondceramic layer of green sheets may be formed on the first heating layer512. A plurality of vias 528 formed through the second heating layer516, the dielectric layer 520, and/or the first heating layer 512connect the bus layer 504 to the first heating layer 512 and the secondheating layer 516 according to a desired configuration (e.g., whetherthe first heating layer 512 and the second heating layer 516 inrespective heating elements are connected in series, in parallel, etc.).

As shown in another example in FIG. 5B, a layer 532 corresponds to afirst ceramic layer of green sheets, which may include a bus layer 536formed thereon. Vias 540 are formed in the layer 532 to connect the buslayer 536 to a power supply and a power return. Green sheets including afirst heating layer 544 and a second heating layer 548 are formed on alayer 552 and the layer 532. The layer 552 corresponds to a secondceramic layer of green sheets, which may include a bus layer 556 formedthereon. A layer 560 corresponding to a third ceramic layer of greensheets may be formed on the first heating layer 544. A plurality of vias564 formed through the second heating layer 548, the layer 552, and/orthe first heating layer 544 connect the bus layer 536 to the firstheating layer 544, the second heating layer 548, and the bus layer 556according to a desired configuration (e.g., whether the first heatinglayer 544 and the second heating layer 548 in respective heatingelements are connected in series, in parallel, etc.).

As shown in an example in FIG. 5C, a layer 568 corresponds to a firstceramic layer of green sheets, which may include a bus layer 572 formedthereon. Vias 576 are formed in the layer 568 to connect the bus layer572 to a power supply and a power return. Green sheets including a firstheating layer 580 with both a first heating material and a secondheating material are formed on the layer 568. In other words, the sameheating layer 580 includes both a positive TCR material and a negativeTCR material (i.e., the first heating material and the second heatingmaterial are substantially coplanar) in contrast to arranging the firstheating material and the second heating material in different layers asshown in FIGS. 5B and 5C. A layer 584 corresponding to a second ceramiclayer of green sheets may be formed on the first heating layer heatinglayer 580.

Referring now to FIGS. 6A, 6B, 6C, and 6D show example configurations ofa single heating layer 600 including both a first heating material 604and a second heating material 608 as described in FIG. 5C. The firstheating material 604 and the second heating material 608 are interwovenin the same heating layer 600 (e.g., in the same plane). In FIG. 6A, thefirst heating material 604 and the second heating material 608 areinterwoven in an “S”-shape. In FIG. 6B, the first heating material 604and the second heating material 608 include interlocking alternatingfingers. In FIG. 6C, the first heating material 604 and the secondheating material 608 are interwoven in a “U”-shape. In FIG. 6D, thefirst heating material 604 and the second heating material 608 areinterwoven in a spiral shape.

As shown in each of FIGS. 6A, 6B, 6C, and 6D, the first heating material604 and the second heating material 608 are connected together in aserial configuration. However, in other examples, the first heatingmaterial 604 and the second heating material 608 may be connectedtogether in a parallel configuration. Power is provided to a first endof the first heating material 604 using a via 612. A second end of thefirst heating material 604 is connected to a first end of the secondheating material 608 using respective vias 616 and 620. A second end ofthe second heating material 608 is connected to a power return using via624.

The foregoing description is merely illustrative in nature and is in noway intended to limit the disclosure, its application, or uses. Thebroad teachings of the disclosure can be implemented in a variety offorms. Therefore, while this disclosure includes particular examples,the true scope of the disclosure should not be so limited since othermodifications will become apparent upon a study of the drawings, thespecification, and the following claims. It should be understood thatone or more steps within a method may be executed in different order (orconcurrently) without altering the principles of the present disclosure.Further, although each of the embodiments is described above as havingcertain features, any one or more of those features described withrespect to any embodiment of the disclosure can be implemented in and/orcombined with features of any of the other embodiments, even if thatcombination is not explicitly described. In other words, the describedembodiments are not mutually exclusive, and permutations of one or moreembodiments with one another remain within the scope of this disclosure.

Spatial and functional relationships between elements (for example,between modules, circuit elements, semiconductor layers, etc.) aredescribed using various terms, including “connected,” “engaged,”“coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and“disposed.” Unless explicitly described as being “direct,” when arelationship between first and second elements is described in the abovedisclosure, that relationship can be a direct relationship where noother intervening elements are present between the first and secondelements, but can also be an indirect relationship where one or moreintervening elements are present (either spatially or functionally)between the first and second elements. As used herein, the phrase atleast one of A, B, and C should be construed to mean a logical (A OR BOR C), using a non-exclusive logical OR, and should not be construed tomean “at least one of A, at least one of B, and at least one of C.”

In some implementations, a controller is part of a system, which may bepart of the above-described examples. Such systems can comprisesemiconductor processing equipment, including a processing tool ortools, chamber or chambers, a platform or platforms for processing,and/or specific processing components (a wafer pedestal, a gas flowsystem, etc.). These systems may be integrated with electronics forcontrolling their operation before, during, and after processing of asemiconductor wafer or substrate. The electronics may be referred to asthe “controller,” which may control various components or subparts ofthe system or systems. The controller, depending on the processingrequirements and/or the type of system, may be programmed to control anyof the processes disclosed herein, including the delivery of processinggases, temperature settings (e.g., heating and/or cooling), pressuresettings, vacuum settings, power settings, radio frequency (RF)generator settings, RF matching circuit settings, frequency settings,flow rate settings, fluid delivery settings, positional and operationsettings, wafer transfers into and out of a tool and other transfertools and/or load locks connected to or interfaced with a specificsystem.

Broadly speaking, the controller may be defined as electronics havingvarious integrated circuits, logic, memory, and/or software that receiveinstructions, issue instructions, control operation, enable cleaningoperations, enable endpoint measurements, and the like. The integratedcircuits may include chips in the form of firmware that store programinstructions, digital signal processors (DSPs), chips defined asapplication specific integrated circuits (ASICs), and/or one or moremicroprocessors, or microcontrollers that execute program instructions(e.g., software). Program instructions may be instructions communicatedto the controller in the form of various individual settings (or programfiles), defining operational parameters for carrying out a particularprocess on or for a semiconductor wafer or to a system. The operationalparameters may, in some embodiments, be part of a recipe defined byprocess engineers to accomplish one or more processing steps during thefabrication of one or more layers, materials, metals, oxides, silicon,silicon dioxide, surfaces, circuits, and/or dies of a wafer.

The controller, in some implementations, may be a part of or coupled toa computer that is integrated with the system, coupled to the system,otherwise networked to the system, or a combination thereof. Forexample, the controller may be in the “cloud” or all or a part of a fabhost computer system, which can allow for remote access of the waferprocessing. The computer may enable remote access to the system tomonitor current progress of fabrication operations, examine a history ofpast fabrication operations, examine trends or performance metrics froma plurality of fabrication operations, to change parameters of currentprocessing, to set processing steps to follow a current processing, orto start a new process. In some examples, a remote computer (e.g. aserver) can provide process recipes to a system over a network, whichmay include a local network or the Internet. The remote computer mayinclude a user interface that enables entry or programming of parametersand/or settings, which are then communicated to the system from theremote computer. In some examples, the controller receives instructionsin the form of data, which specify parameters for each of the processingsteps to be performed during one or more operations. It should beunderstood that the parameters may be specific to the type of process tobe performed and the type of tool that the controller is configured tointerface with or control. Thus as described above, the controller maybe distributed, such as by comprising one or more discrete controllersthat are networked together and working towards a common purpose, suchas the processes and controls described herein. An example of adistributed controller for such purposes would be one or more integratedcircuits on a chamber in communication with one or more integratedcircuits located remotely (such as at the platform level or as part of aremote computer) that combine to control a process on the chamber.

Without limitation, example systems may include a plasma etch chamber ormodule, a deposition chamber or module, a spin-rinse chamber or module,a metal plating chamber or module, a clean chamber or module, a beveledge etch chamber or module, a physical vapor deposition (PVD) chamberor module, a chemical vapor deposition (CVD) chamber or module, anatomic layer deposition (ALD) chamber or module, an atomic layer etch(ALE) chamber or module, an ion implantation chamber or module, a trackchamber or module, and any other semiconductor processing systems thatmay be associated or used in the fabrication and/or manufacturing ofsemiconductor wafers.

As noted above, depending on the process step or steps to be performedby the tool, the controller might communicate with one or more of othertool circuits or modules, other tool components, cluster tools, othertool interfaces, adjacent tools, neighboring tools, tools locatedthroughout a factory, a main computer, another controller, or tools usedin material transport that bring containers of wafers to and from toollocations and/or load ports in a semiconductor manufacturing factory.

What is claimed is:
 1. A method of forming a substrate support in a substrate processing system, the method comprising: forming at least one ceramic layer; and arranging a plurality of thermal elements adjacent to the ceramic layer in one or more thermal zones, wherein each of the thermal zones includes at least one of the thermal elements, wherein each of the thermal elements includes a first resistive material having a positive thermal coefficient of resistance (TCR), and a second resistive material having a negative TCR, wherein the second resistive material is electrically connected to the first resistive material, and wherein at least one of the first resistive material and the second resistive material of each of the thermal elements is electrically connected to a power supply to receive power, and wherein each of the thermal elements heats a respective one of the thermal zones based on the received power.
 2. The method of claim 1, wherein forming the at least one ceramic layer includes forming a first ceramic layer and a second ceramic layer, wherein the thermal elements are arranged in a heating layer formed on the first ceramic layer, and wherein the second ceramic layer is formed on the heating layer.
 3. The method of claim 2, wherein forming the heating layer includes depositing a metallized layer on a surface of the at least one ceramic layer.
 4. The method of claim 1, wherein respective absolute values of the positive TCR and the negative TCR are substantially equal.
 5. The method claim 1, wherein a sum of the positive TCR and the negative TCR is zero.
 6. The method of claim 1, further comprising connecting the first resistive material and the second resistive material in series.
 7. The method of claim 1, further comprising connecting the first resistive material and the second resistive material in parallel.
 8. The method of claim 1, further comprising arranging the first resistive material above the second resistive material.
 9. The method of claim 8, further comprising arranging the first resistive material directly above the second resistive material.
 10. The method of claim 8, further comprising laterally offsetting the first resistive material from the second resistive material.
 11. The method claim 1, further comprising arranging the first resistive material to be coplanar with the second resistive material.
 12. The method of claim 11, further comprising interweaving the first resistive material and the second resistive material.
 13. The method of claim 12, wherein the first resistive material and the second resistive material are interwoven to form at least one of an “S”-shape, a spiral shape, and a “U”-shape.
 14. The method of claim 12, wherein the first resistive material and the second resistive material include alternately interlocking fingers. 